Data.ByteString.Char8 does not export stripSuffix - haskell

Question

I'm working on a stream of ByteStrings. I've imported ByteString via:
import qualified Data.ByteString as B
I can call every function from the ByteString library e.g.:
reverseBS :: Monad m => Conduit B.ByteString m B.ByteString
reverseBS = CL.map B.reverse
This works as intended.
I need a function to remove the trailing newline from a ByteString. I've opted to use stripSuffix from ByteString. My code looks like this:
removeNewline :: Monad m => Conduit B.ByteString m B.ByteString
removeNewline = CL.map $ B.stripSuffix "\n"
But my code won't compile and gives the following error:
Not in scope: ‘B.stripSuffix’
I've tried install the latest version of ByteString from GitHub but this didn't help.
EDIT:
I noticed that there's something wrong with my ghc-pkg list. It give me the following output:
Thomass-MacBook-Pro:src ThomasVanhelden$ ghc-pkg list
/Applications/ghc-7.10.3.app/Contents/lib/ghc-7.10.3/package.conf.d
Cabal-1.22.5.0
array-0.5.1.0
base-4.8.2.0
bin-package-db-0.0.0.0
binary-0.7.5.0
bytestring-0.10.6.0
containers-0.5.6.2
deepseq-1.4.1.1
directory-1.2.2.0
filepath-1.4.0.0
ghc-7.10.3
ghc-prim-0.4.0.0
haskeline-0.7.2.1
hoopl-3.10.0.2
hpc-0.6.0.2
integer-gmp-1.0.0.0
pretty-1.1.2.0
process-1.2.3.0
rts-1.0
template-haskell-2.10.0.0
terminfo-0.4.0.1
time-1.5.0.1
transformers-0.4.2.0
unix-2.7.1.0
xhtml-3000.2.1
/Users/ThomasVanhelden/.ghc/x86_64-darwin-7.10.3/package.conf.d
WAVE-0.1.3
abstract-deque-0.3
abstract-par-0.3.3
async-2.1.1
attoparsec-0.13.1.0
base16-bytestring-0.1.1.6
base64-bytestring-1.0.0.1
blaze-builder-0.4.0.2
bytestring-0.10.8.2
bytestring-lexing-0.5.0.2
cereal-0.5.4.0
chunked-data-0.3.0
conduit-1.2.8
conduit-combinators-1.0.8.3
conduit-extra-1.1.15
exceptions-0.8.3
extensible-exceptions-0.1.1.4
fail-4.9.0.0
hashable-1.2.4.0
lifted-base-0.2.3.8
mmorph-1.0.9
monad-control-1.0.1.0
monad-par-0.3.4.8
monad-par-extras-0.3.3
mono-traversable-1.0.1
mtl-2.2.1
mwc-random-0.13.5.0
network-2.6.3.1
network-conduit-1.1.0
parallel-3.2.1.0
parallel-io-0.3.3
parseargs-0.2.0.8
primitive-0.6.1.0
random-1.1
resourcet-1.1.8.1
scientific-0.3.4.9
semigroups-0.18.2
split-0.2.3.1
stm-2.4.4.1
streaming-commons-0.1.16
tagged-0.8.5
text-1.2.2.1
transformers-base-0.4.4
transformers-compat-0.5.1.4
unix-compat-0.4.2.0
unordered-containers-0.2.7.1
vector-0.11.0.0
vector-algorithms-0.7.0.1
void-0.7.1
word8-0.1.2
zlib-0.6.1.2
It looks like it is looking in two different directories for packages and two different versions of ByteString might be the cause of the problem. How can I solve this? Is there a simple way to uninstall bytestring-0.10.6.0?

Answer 1

Firs of all, it is worth mentioning that stripSuffix was indeed introduced in version 0.18 of bytestring. Quoting the changelog:
0.10.8.0 Duncan Coutts duncan#community.haskell.org May 2016
[etc.]
Added stripPrefix and stripSuffix for lazy and strict bytestrings
That sad, onward to your question:
Is there a simple way to uninstall bytestring-0.10.6.0?
No, there isn't, because, as the ghc-pkg output tells you, the 0.10.6.0 version is among the packages installed globally (i.e. system-wide rather than per-user). Uninstalling it would break all the other packages you had installed previously that depend on bytestring. When you installed bytestring from GitHub, it went to your per-user package database. To avoid further headache, the first thing I suggest is getting rid of the newer bytestring that you have installed, with:
ghc-pkg unregister bytestring-0.10.8.2
Then, to get the latest bytestring, you should update the Haskell installation in your system (for instance, the latest minimal Haskell Platform carries bytestring-0.10.8.1). Alternatively, you can use Stack to manage multiple GHC versions (as well as appropriate package databases for them) for your projects.